Herbicidal 1-alkanoyloxy-haloethyl urea

ABSTRACT

Herbicidal compounds of the formula ##STR1## wherein R is alkyl, cycloalkyl or phenyl substituted with up to 2 fluorine, chlorine, bromine, trifluoromethyl, nitro, lower alkoxy, lower alkyl, or phenoxy, phenylthio or phenylsulfonyl substituted with up to 2 fluorine or chlorine atoms; R 1  is hydrogen or alkyl; R 2  is alkyl; Z is halogen; Y is hydrogen or Z; and R 3  is hydrogen or alkyl.

RELATED APPLICATIONS

This application is a division of application Ser. No. 423,598, filed Dec. 10, 1973, now U.S. Pat. No. 3,916,010, which, in turn, is a continuation-in-part of application Ser. No. 385,521, filed Aug. 3, 1973 now abandoned, which is, in turn, a continuation-in-part of application Ser. Nos. 124,422 and 124,423, filed Mar. 16, 1971 both now abandoned. The disclosure of Ser. No. 385,521 is incorporated herein by reference.

DESCRIPTION OF THE PRIOR ART

Chattaway et al, Proc. Roy. Soc. (London) A-134, pp. 372-84 (1931), and Chattaway et al, J. Chem. Soc. 1933 30, disclose compounds prepared by the condensation of chloral with aryl ureas, and the acetylation of the resulting condensation products with acetic anhydride to produce diacetyl ureas and/or bis-ureido ethers.

U.S. Pat. No. 3,040,082 and Hoover et al, J. Org. Chem. 28(7), 1825-30 (1963) disclose β-polyhalo-α-hydrocarbyl isocyanates and derivatives thereof, such as 1-(1-hydroxy-2,2,2-trifluoroethyl)-3-phenyl urea and 1-(1-hydroxy-2,2,2-trichloroethyl)-3-phenyl urea, and their use as herbicides.

Also, U.S. Pat. Nos. 2,846,399, 2,902,356, 3,418,334 and 3,488,376 disclose ureas and their uses.

DESCRIPTION OF THE INVENTION

Compounds of the present invention may be represented by the formula (I) ##STR2## wherein R is alkyl of 1 to 12 carbon atoms, cycloalkyl of 3 to 8 carbon atoms, or phenyl substituted with up to 2 (0 to 2) fluorine, chlorine, bromine, trifluoromethyl, nitro, lower alkoxy, lower alkyl, or phenoxy, phenylthio or phenylsulfonyl substituted with up to 2 fluorine or chlorine; R¹ is hydrogen or alkyl of 1 to 4 carbon atoms; R² is alkyl of 1 to 4 carbon atoms; Z is chlorine or bromine; Y is hydrogen or Z; and R³ is hydrogen or alkyl of 1 to 6 carbon atoms.

Preferably R is alkyl of 1 to 6 carbon atoms, cycloalkyl of 5 to 6 carbon atoms or phenyl substituted with 1 to 2 fluorine, chlorine, bromine, trifluoromethyl, nitro, lower alkoxy or lower alkyl groups. More preferably, R is phenyl substituted with 1 to 2 fluorine or chlorine. A single trifluoromethyl or fluorine group is preferably attached to the phenyl in the ortho position. Preferably Y is chlorine or bromine, R¹ is hydrogen and R² is alkyl of 1 to 4 carbon atoms. More preferably R² is methyl. R³ is preferably hydrogen.

Representative groups which R may represent include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.butyl, decyl, dodecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, 2-fluorophenyl, 2-chlorophenyl, 2-chloro-4-bromophenyl, 3-methylphenyl, 4-methoxyphenyl, 2-nitrophenyl, 2-trifluoromethylphenyl, 4-phenoxyphenyl, 4-phenylthiophenyl, 4-phenylsulfonylphenyl, and 4-(2-chlorophenoxy)phenyl.

Representative alkyl groups which R¹, R² and R³ may represent include hydrogen, methyl, ethyl, n-propyl, isopropyl, butyl, hexyl, etc.

Representative compounds of the invention include:

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(4-phenoxyphenyl urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(4-[4'-chlorophenoxy]phenyl) urea,

1-ethyl-1-(1-formyloxy-2,2,2-tribromomethyl)-3-(4-phenylsulfonylphenyl) urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-phenyl urea,

1-ethyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(2-trifluoromethylphenyl) urea,

1-methyl-1-(1-formyloxy-2,2,2-tribromoethyl)-3-(2-fluorophenyl) urea,

1-butyl-1-(1-formyloxy-2,2-dichloro-2-bromoethyl)-3-(2-nitrophenyl) urea,

1-methyl-1-(1-formyloxy-2,2-dichloroethyl)-3-(4-methylphenyl) urea,

1-butyl-1-(1-formyloxy-2,2,2-trifluoroethyl)-3-(4-methoxyphenyl) urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-methyl urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-dodecyl urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-cyclopentyl urea,

1-methyl-1-(1-propionyloxy-2,2,2-trichloroethyl)-3-cyclohexyl urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(4-phenylthiophenyl) urea,

1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(2-bromophenyl) urea,

1-methyl-1-(1-acetoxy-2,2,2-tribromoethyl)-3-(2-chlorophenyl) urea,

1-methyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(4-nitrophenyl) urea,

1-methyl-1-(1-acetoxy-2-bromo-2,2-dichloroethyl)-3-(3-chloro-4-methoxyphenyl) urea,

1-methyl-1-(1-propionyloxy-2,2,2-trichloroethyl)-3-(2-fluorophenyl) urea,

1-methyl-1-(1-butyryloxy-2-bromo-2,2-dichloroethyl)-3-(3-chlorophenyl) urea,

1-methyl-1-(1-pentanoyloxy-2,2-dichloroethyl)-3-(2,4-dichlorophenyl) urea,

1-methyl-1-(1-n-hexanoyloxy-2,2,2-trichloroethyl)-3-(2-nitrophenyl) urea, and

1-ethyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(2-methyl-4-chlorophenyl) urea.

The preferred compounds of the invention are those wherein R, R¹ and R² are as defined above, R³ is hydrogen and Y and Z are chlorine.

The preparation of compounds of the present invention begins with the α-hydroxy compounds represented by formula (IV). Such compounds are prepared by reacting a urea with an aldehyde according to the following reaction (1) ##STR3## wherein R, R¹, R², Y and Z are as defined above.

The urea reactants (II) employed for reaction (1) are known compounds of the prior art. The aldehyde (III) may be a compound such as chloral (trichloroacetaldehyde), dichloroacetaldehyde, dichlorobromoacetaldehyde, tribromoacetaldehyde, etc. Reaction (1) may be accomplished in the presence of a solvent or neat. Generally, stoichiometric amounts of the urea and aldehyde will be used. A small amount of acid, preferably sulfuric acid or perchloric acid, may be used. The reaction temperature will be from 20° to 100° C. Generally the reaction proceeds very rapidly and will be complete in a matter of a few minutes. Reaction times of from 30 seconds to 10 hours are considered sufficient.

The α-hydroxy compound (IV) is then converted to the α-chloro compound represented by formula (V) by reacting the α-hydroxy compound (IV) either in purified form or in the reaction mixture of reaction (1) with thionyl chloride according to the following reaction (2): ##STR4## wherein R, R¹, R², Y and Z are as defined above.

The reaction (2) can be accomplished by using from a molar amount of thionyl chloride to an excess of as much as 20 mols, based on the urea. The reaction temperature will be from 20° to 100° C. and reaction time will be from 1 to 20 hours. If desired, reactions (1) and (2) may be combined to prepare the α-chloro compound (V) by simply mixing together the urea reactant (II), the aldehyde reactant (III) and the thionyl chloride. The α-chloro product (V) can be recovered by slurrying in a solvent such as diethyl ether or methylene chloride, collecting the product on a filter, then purifying by recrystallizing from inert solvents such as a 1:1 mixture of 1,2-dimethoxymethane and methylene chloride or a 1:1 acetone and methylene chloride mixture.

The compounds of the present invention are prepared by reacting the α-chloro compound (V) with ammonium formate or alkanoate as shown in reaction (3) below: ##STR5## wherein R, R¹, R², R³, Z and Y are as defined above.

The above reaction (3) can be accomplished readily by mixing the reactants preferably in a solvent such as 1,2-dimethoxyethane in an amount from 2 to 50% by volume for a time from about 0.25 to 20 hours at a temperature from about 20° to 100° C. The solvent is then removed and the product is isolated and purified by conventional methods such as extraction, filtration, recrystallization, etc. Generally the ammonium formate or alkanoate will be in excess, in an amount of 5 to 100% of the α-chloro urea reactant (V).

The formyloxy-substituted ureas of formulas (I), (II) or (III) can also be prepared by reacting the α-chloro compound (V) with formic acid in the presence of an acid acceptor, according to the following reaction (4): ##STR6## wherein R, R¹, R², Z and Y are as defined above and B is an acid acceptor.

The above reaction (4) is readily accomplished by contacting α-chloro urea (V) with an excess of formic acid of up to 20 mols, based on the urea (V), at a temperature of 0° to 50° C. Suitable acid acceptors are organic nitrogen bases having no free N-H groups such as trialkylamines, e.g., trimethylamine and triethylamine, and pyridine compounds, e.g., pyridine and 2-methylpyridine. The molar ratios of acid acceptor to urea (V) is substantially equimolar, e.g., 1.5:1 to 1:1.5. The α-formyloxy product (VII) is isolated and purified by conventional methods such as filtration, extraction, crystallization, etc.

The present invention will be more fully understood by reference to the following examples.

EXAMPLES Example 1 -- Preparation of 1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-phenyl urea

1-methyl-3-phenyl urea (7.5 g, 0.05 mol) was reacted with 7.5 g (0.05 mol) of chloral without solvent. The mixture was shaken for a short period of time. After, 3 drops of perchloric acid were added and the mixture heated gently for a few minutes to give a homogenous viscous oil. Upon cooling, the product formed as a glass. The chemical analysis showed: %Cl, calculated 35.8, found 35.8; %N, calculated 9.4, found 8.0. The product is the fifth compound tabulated in Table I.

Example 2 -- Preparation of 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-fluorophenyl) urea

N-methyl-N'-o-fluorophenyl urea (16.8 g, 0.1 mol) was combined with 22.5 g (0.15 mol) chloral and 18.0 g (0.15 mol) thionyl chloride. After several minutes an exothermicity was noted and the reaction mixture became a homogenous yellow oil. After 5 minutes more, a precipitate began to form. After 11/2 hours a 3:1 mixture of diethyl ether:petroleum ether was added and the product was collected on a filter and dried. The product weighed 25 g, melted at 130°-141° C. and analyzed as follows: %Cl, calculated 35.7, found 37.3; %N, calculated 9.5, found 9.5. The product is the sixth compound tabulated in Table I.

Example 3 -- Preparation of 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,4-dichlorophenyl) urea

1-(3,4-dichlorophenyl)-3-methyl urea (15.2 g, 0.07 mol) was combined with 15.0 g (0.1 mol) of chloral and 5 drops of concentrated sulfuric acid. The mixture was heated for an hour to effect reaction, then stripped under vacuum. To the crude 1-(3,4-dichlorophenyl)-3-(1-hydroxy-2,2,2-trichloroethyl)-3-methyl urea was added an excess of thionyl chloride and the mixture was heated gradually to a maximum of 65° C. Diethyl ether was added to the crude product, and the insoluble product was collected on a filter, washed twice with diethyl ether and dried. The 15.3 g of product, which melted at 132°-140° C., analyzed as follows: %Cl, calculated 55.2, found 46.0. The product is the seventh compound tabulated in Table I.

Example 4 -- Preparation of 1-methyl- 1(1,2,2,2-tetrachloroethyl)-3-(4-phenoxyphenyl) urea.

p-Phenoxyaniline (11.7 g, 0.063 mol) was dissolved in 25 ml. 1,2-dimethoxyethane (Ansul E-121) and heated to 65° C. Methyl isocyanate (3.7 g, 0.65 mol) was added over a period of 10 minutes. Heating and stirring were continued for 1 hour. Then chloral (14.8 g, 0.1 mol) was added to the hot solution, followed immediately by the addition of 11.9 g (0.1 mol) thionyl chloride. It was kept at 65° C. for 41/2 hours. The solution was cooled to 40°, and 25 ml of methylene chloride was added. The solution was refluxed for one more hour and then allowed to cool. The solid which formed upon cooling was filtered, washed with methylene chloride to give 5.0 g (20% yield) of the product, as a white powder, melting point 165°-167° C. A second crop, melting point 160°-162° C., weighed 5.5 g (22%). Elemental analysis showed: %Cl, calc. 34.8, found 34.4; %N, calc. 6.9, found 6.8; %C, calc. 47.1, found 47.5; %H, calc. 3.46, found 3.3. The product is the eighth compound tabulated in Table I.

EXAMPLE 5 -- Preparation of 1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(3,4-dichlorophenyl) urea

Triethylamine (2 g, 0.02 mol) was added slowly to a slurry of 4.4 g (0.02 mol) 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,4-dichlorophenyl) urea in 50 ml formic acid. After stirring for about 15 minutes, a precipitate of triethylamine hydrochloride formed. The reaction mixture was then poured into 300 ml water, filtered and dried. The resulting crude product melted at 136°-145° C. The crude product was then diluted with 15-20 ml benzene and filtered. The filtrate was concentrated to about 10-15 ml and diluted with 50ml hexane to precipitate the product as a while solid, m.p. 138°-140° C. Analysis was as follows: %C, calc. 33.5, found 33.8; %H, calc. 2.3, found 2.1; %N, calc. 7.1, found 7.1. The product is the first compound tabulated in Table I.

Example 6 -- Preparation of 1-methyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(3,4-dichlorophenyl) urea

1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,4-dichlorophenyl) urea (7.7 g, 0.02 mol) was dissolved in 200 ml dimethoxyethane, followed by the addition of 1.5 g of ammonium acetate. The mixture was stirred for 2 hours, filtered, and stripped of solvent. The residual mush was added to ether and the ether-insoluble material filtered off. Next, the ether was removed under vacuum. The residual oil was added to chloroform and some undissolved material was removed by filtration. The filtrate was evaporated to give 5.5 g of the product, as an oil. The infrared and NMR spectra were consistent with the assigned structure. The chlorine analysis was: %Cl, calc. 43.5, found 41.7. The product is the third compound tabulated in Table I.

Other compounds and intermediates of the present invention were prepared using the methods as described above. These compounds are listed in Table I.

UTILITY

The ureas of the present invention are, in general, herbicidal in both pre- and post-emergent applications. For pre-emergent control of undesirable vegetation, these ureas will be applied in herbicidal quantities to the environment, e.g., soil infested with seeds and/or seedlings of such vegetation. Such application will inhibit the growth of or kill the seeds, germinating seeds and seedlings. For post-emergent applications, the ureas of the present invention will be applied directly to the foliage and other plant parts. Generally they are effective against weed grasses as well as broadleaved weeds. Some may be selective with respect to type of application and/or type of weed.

Pre- and post-emergent herbicidal tests on representative ureas of this invention were made using the following methods:

Pre-Emergent Test

Acetone solutions of the test ureas were prepared by mixing 750 mg urea, 220 mg of a nonionic surfactant and 25 ml of acetone. This solution was added to approximately 125 ml of water containing 156 mg of surfactant.

Seeds of the test vegetation were planted in a pot of soil and the urea solution was sprayed uniformly onto the soil surface at a dose of 100 mcg per cm². The pot was watered and placed in a greenhouse. The pot was watered intermittently and was observed for seedling emergence, health of emerging seedlings, etc., for a 3-week period. At the end of this period, the herbicidal effectiveness of the urea was rated, based on the physiological observations. A 0-to-100 scale was used, 0 representing no phytotoxicity, 100 representing complete kill.

Post-Emergent Test

The test ureas were formulated in the same manner as described above for the pre-emergent test. The concentration of the urea in this formulation was 5000 ppm. This formulation was uniformly sprayed on 2 similar pots of 24-day-old plants (approximately 15 to 25 plants per pot) at a dose of 100 mcg per cm². After the plants had dried, they were placed in a greenhouse and then watered intermittently at their bases, as needed. The plants were observed periodically for phytotoxic effects and physiological and morphological responses to the treatment. After 3 weeks the herbicidal effectiveness of the urea was rated, based on these observations. A 0-to-100 scale was used, 0 representing no phytotoxicity, 100 representing complete kill.

The results of these tests appear in Table II.

The amount of urea administered will vary with the particular plant part or plant growth medium which is to be contacted, the general location of application -- i.e., sheltered areas such as greenhouses as compared to exposed areas such as fields -- as well as the desired type of control. For pre-emergent control of most plants, dosages in the range of about 0.5 to 20 lbs per acre will be used. Such administration will give a concentration of about 2 to 80 ppm urea distributed throughout 0.1 acre-foot. For post-emergent application, such as foliar spray application, compositions containing about 0.5 to 8 lbs per urea per 100 gals spray will be used. Such application is equivalent to about 0.5 to 20 lbs urea per acre.

The herbicidal compositions of this invention comprise an herbicidal amount of one of more of the above-described ureas intimately admixed with a biologically inert carrier. The carrier may be a liquid diluent, such as water or acetone, or a solid. The solid may be in the form of dust powder or granules. These compositions will also usually contain adjuvants such as a wetting or dispersing agent to facilitate their penetration into the plant growth medium or plant tissue and generally enhance their effectiveness. These compositions may also contain other pesticides, stabilizers, conditioners, fillers, and the like.

                                      Table I                                      __________________________________________________________________________                                         Elemental Analysis   Melting                                                   Halogen                                                                               N      S      Point,                            Compound                Calc.                                                                             Found                                                                              Calc.                                                                             Found                                                                              Calc.                                                                             Found                                                                              °              __________________________________________________________________________                                                              C                     1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl-3-(3,4-dichloro-                   phenyl) urea                              7.1                                                                               7.1        138-140               1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(2-fluro-                       phenyl) urea                       38.4                                                                              38.8              124-127               1-methyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(3,4-dichloro-                    phenyl) urea                       43.5                                                                              41.7               oil                  1-methyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(3-chloro-                        phenyl) urea                       38.0                                                                              34.6                                                                               7.5                                                                               7.0        150-152               1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-phenyl urea                                                          35.8                                                                              35.8                                                                               9.4                                                                               8.0        --                    1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-fluorophenyl)                                                           35.7                                                                              37.3                                                                               9.5    130-141                      1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,4-dichlorophenyl)                    urea                               55.2                                                                              46.0              132-140               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(4-phenoxyphenyl)                                                          34.8                                                                              34.4                                                                               6.9                                                                               6.8        165-167               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-chlorophenyl)                                                           45.2                                                                              49.4              139-145               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(4-chlorophenyl)                                                           45.2                                                                              41.9              175-180               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2,4-dichlorophenyl                     urea                               45.5                                                                              43.6              190-193               1-methyl-1-1-(1,2,2,2-tetrachloroethyl)-3-(4-bromophenyl)                                                          12.7.sup.1                                                                        13.4.sup.1        187-190               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3-chlorophenyl)                                                           50.6                                                                              50.0                                                                               8.0                                                                               7.3        155-160               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-phenyl urea                                                                44.9                                                                              34.4                                                                               8.9                                                                               8.4        164-166               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3-chloro-4-bromo-                      phenyl) urea                       14.0.sup.1                                                                        13.7.sup.1                                                                         6.5                                                                               6.2        189-190               1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-(3-chloro-                        phenyl) urea                       42.8                                                                              39.4                                                                               8.4                                                                               9.5         oil                  1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-trifluoro-                                                            Cl                                                                               30.6                                                                              30.9                                     methylphenyl) urea               F 16.4                                                                              16.2              145-148               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,5-dichloro-                          phenyl) urea                       55.4                                                                              50.3                                                                               7.3                                                                               7.5        150-157               1-methyl-1-(1,2,2-trichloro-2-bromoethyl)-3-(2-fluoro-                          phenyl) urea                       10.6.sup.1                                                                        10.5.sup.1        139-142               1-methyl-1-(1-bromo-2,2,2-trichloroethyl)-3-(2-fluoro-                          phenyl) urea                     Br.sup.3                                                                         21.2                                                                              21.5              153-155               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(4-methoxy-                             phenyl) urea                       41.1                                                                              40.1                                                                               8.1                                                                               8.2        176-179               1-methyl-1-(1,2,2-trichloro-2-bromoethyl)-3-(3,4-                               dichlorophenyl) urea               14.0.sup.1                                                                        13.8.sup.1        166-169               1-methyl-1-(1,2,2-trichloro-2-bromoethyl)-3-(3-chloro-                          phenyl) urea                     Cl.sup.3                                                                         9.0                                                                               8.4               150-152               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3-trifluoro-                                                            Cl.sup.3                                                                         9.3                                                                               9.2                                      methylphenyl) urea               F 14.8                                                                              14.9              138-142               1-methyl-1-(1,2-dibromo-2,2-dichloroethyl)-3-(2-fluoro-                         phenyl) urea                     Br.sup.3                                                                         19.5                                                                              16.2                                                                               6.8                                                                               7.5        130-133               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-[3-methyl-                              4-(4'-chlorophenylthio)phenyl]urea 37.5                                                                              35.4       6.8                                                                               6.8 152-154               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-[3-methyl-4-(4'-                        chlorophenylsulfonyl)phenyl] urea  35.1                                                                              29.0       6.3                                                                               6.8 168-171               1-methyl-1-(1,2,2-trichloroethyl)-3-(3-chlorophenyl) urea                                                                 8.9                                                                               8.9 38.0.sup.2                                                                        38.0.sup.2                                                                         118-127               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-[4-(4'-chloro-                          phenoxy)phenyl]  urea              40.1                                                                              39.6                                                                               6.3                                                                               6.3        153-156               1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-(pyridyl)                                                            35.6                                                                              32.2                                                                               14.1                                                                              12.0       oil                   1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-(2-thiazolyl)                     urea                               34.9                                                                              35.8              oil                   1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-(2-pyridyl)                                                          35.6                                                                              33.6              oil                   1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-(2-pyrimidyl)                     urea                               35.5                                                                              35.4                                                                               18.7                                                                              18.2       100-104               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-cyclopentyl urea                                                                  9.1                                                                               8.7        132-136               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-cyclohexyl urea                                                                   8.7                                                                               8.4        127-129.5             1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-methyl urea                                                                       11.0                                                                              10.9       73-76                 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-n-hexyl urea                                                                      8.7                                                                               9.2        45-55                 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-t-butyl urea                                                                      9.5                                                                               9.7 32.5.sup.2                                                                        31.7.sup.2                                                                         84-88                 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-n-dodecyl urea                                                             34.7                                                                              33.5                                                                               6.9                                                                               6.3        39-41                 1-methoxy-1-(1,2,2,2-tetrachloroethyl)-3-(2-fluoro-                                                              Cl                                                                               40.6                                                                              40.2                                     phenyl) urea                     F 5.4                                                                               5.8               75-78                 1-methyl-1-(1-chloro-2,2,2-tribromoethyl)-3-(3,4-dichloro-                      phenyl) urea                       11.6.sup.1                                                                        11.6.sup.1                                                                         5.4                                                                               5.5        155-158               __________________________________________________________________________      .sup.1 analysis for total halogen in milliequivalents per gram                 .sup.2 carbon analysis                                                         .sup.3 analysis for active halogen (i.e., the halogen on the carbon            adjacent to the 1-nitrogen atom)                                         

                                      TABLE II                                     __________________________________________________________________________                                     Herbicidal Effectiveness                                                       Pre/Post                                                   Compound            O    W    C    M    P     L                    __________________________________________________________________________     1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(3,4-                          dichlorophenyl) urea            60/65                                                                               95/90                                                                               100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(2-                            fluorophenyl) urea              100/60                                                                              100/30                                                                              100/0                                                                               100/65                                                                              100/90                                                                               100/75               1-methyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(3,4-                            dichlorophenyl) urea            40/0 100/55                                                                              100/10                                                                              100/100                                                                             100/100                                                                              100/00               1-methyl-1-(1-acetoxy-2,2,2-trichloroethyl)-3-(3-                              chlorophenyl) urea              75/95                                                                               100/100                                                                             90/100                                                                              95/100                                                                              90/100                                                                               95/100               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-fluorophenyl)                       urea                            100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,4-                                  dichlorophenyl) urea            90/100                                                                              100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2-trichloroethyl)-3-(4-phenoxyphenyl) urea                                                     90/  95/  100/ 100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-chloro-                             phenyl) urea                    90/80                                                                               97/80                                                                               93/85                                                                               100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(4-chloro-                             phenyl) urea                    100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2,4-                                  dichlorophenyl) urea            70/70                                                                               92/85                                                                               100/75                                                                              100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(4-bromo-                              phenyl) urea                    65/50                                                                               90/90                                                                               95/0 100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3-chloro-                             phenyl) urea                    90/70                                                                               100/85                                                                              95/60                                                                               100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-phenyl urea                                                            100/100                                                                             100/100                                                                             100/85                                                                              100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3-chloro-                             4-bromophenyl) urea             50/95                                                                               80/100                                                                              100/95                                                                              99/100                                                                              100/100                                                                              100/100              1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-(3-                              chlorophenyl) urea              85/100                                                                              95/100                                                                              95/100                                                                              90/100                                                                              90/100                                                                               90/100               1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(2-trifluoro-                          methylphenyl) urea              --   96/  91/  /85  /90   /85                  1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3,5-                                  dichlorophenyl) urea            --   --   --   100/80                                                                              100/  100/70               1-methyl-1-(2-bromo-1,2,2-trichloroethyl)-3-(2-                                fluorophenyl urea               100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1-bromo-1,2,2-trichloroethyl)-3-(2-                                fluorophenyl) urea              100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(4-                                    methyoxyphenyl) urea            90/  100/ 100/ 95/100                                                                              95/95 95/100               1-methyl-1-(2-bromo-1,2,2-trichloroethyl)-3-                                   (3,4-dichlorophenyl) urea       70/95                                                                               95/100                                                                              /100 95/100                                                                              95/100                                                                               95/100               1-methyl-1-(2-bromo-1,2,2-trichloroethyl)-3-(3-chloro-                         phenyl) urea                    100/100                                                                             100/100                                                                             100/85                                                                              100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-(3-tri-                                fluoromethylphenyl) urea        90/90                                                                               100/100                                                                             100/95                                                                              95/100                                                                              95/100                                                                               100/100              1-methyl-1-(1,2-dibromo-2,2-dichloroethyl)-3-                                  (2-fluorophenyl) urea           /100 /100 /100 /100 /100  /100                 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-[3-methyl-                             4-(4'-chlorophenylthio)phenyl] urea                                                                            --   --   --   /100 /100  /100                 1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-[3-methyl-                             4-(4'-chlorophenylsulfonyl)phenyl] urea                                                                        --   --   --   /100 /90   /95                  1-methyl-1-(1,2,2-trichloroethyl)-3-(3-chlorophenyl) urea                                                      100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                             100/100                                                                              100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-                                       [4-(4'-chlorophenoxy)phenyl] urea                                                                              --   --   --   90/  100/100                                                                              100/100              1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-                                   3-(3-pyridyl) urea              90/  90/  95/  --   --    /90                  1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-                                 (2-thiazolyl) urea              85/  90/  85/  95/100                                                                              100/90                                                                               100/100              1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-                                 (2-pyridyl) urea                /95  80/95                                                                               /90  /100 70/100                                                                               90/100               1-methyl-1-(1-hydroxy-2,2,2-trichloroethyl)-3-                                 (2-pyrimidyl) urea              70/  90/  90/  --   /70   --                   1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-cyclopentyl urea                                                       --   95/  95/90                                                                               95/100                                                                              100/95                                                                               100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-cyclohexyl urea                                                        100/90                                                                              95/85                                                                               95/  100/100                                                                             100/95                                                                               100/100              1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-methyl urea                                                            80/  90/  90/  --   90/   70/                  1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-n-hexyl urea                                                           --   --   --   /100 /95   /95                  1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-t-butyl urea                                                           90/  90/  90/  70/  --    --                   1-methyl-1-(1,2,2,2-tetrachloroethyl)-3-n-dodecyl urea                                                         80/  90/  90/  /70  95/80 100/80               __________________________________________________________________________      O = Wild Oats (Avena fatua)                                                    W = Watergrass (Echinochloa crusgalli)                                         C = Crabgrass (Digitaria sanginalis)                                           M = Mustard (Brassica arvensis)                                                P = Pigweed (Amaranthus retroflexus)                                           L = Lambsquarter (Chenopodium album)                                      

What is claimed is:
 1. A method for controlling undesirable vegetation which comprises applying thereto an herbicidally effective amount of a compound of the formula ##STR7##wherein R is phenyl substituted with 1 to 2 fluorine or chlorine; R¹ is hydrogen or alkyl of 1 to 4 carbon atoms, R² is alkyl of 1 to 4 carbon atoms; Z is chlorine or bromine; Y is hydrogen or Z, and R³ is hydrogen.
 2. The method of claim 1 wherein R¹ is hydrogen.
 3. The method of claim 2 wherein Z and Y are chlorine.
 4. The method of claim 3 wherein the compound is 1-Methyl-(1-formyloxy-2,2,2-trichloroethyl)-3-(2-fluorophenyl) urea.
 5. The method of claim 3 wherein the compound is 1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(3,4-dichlorophenyl) urea.
 6. The method of claim 1 wherein the compound is applied pre-emergently.
 7. The method of claim 1 wherein the compound is applied post-emergently.
 8. A herbicidal composition comprising an herbicidally effective amount of the compound of the formula ##STR8##wherein R is phenyl substituted with 1 to 2 fluorine or chlorine; R¹ is hydrogen or alkyl of 1 to 4 carbon atoms; R² is alkyl of 1 to 4 carbon atoms; Z is chlorine or bromine; Y is hydrogen or Z and R³ is hydrogen, and a biologically inert carrier.
 9. The composition of claim 8 wherein R¹ is hydrogen.
 10. The composition of claim 9 wherein Z and Y are chlorine.
 11. The composition of claim 10 wherein the compound is 1-Methyl-(1-formyloxy-2,2,2-trichloroethyl)-3-(2-fluorophenyl) urea.
 12. The composition of claim 10 wherein the compound is 1-methyl-1-(1-formyloxy-2,2,2-trichloroethyl)-3-(3,4-dichlorophenyl) urea. 